1. Field of the Invention
The present invention is generally in the field of electrical circuits. More particularly, the invention is in the field of voltage conversion circuits.
2. Background Art
Buck converters are commonly utilized to convert a high DC voltage to a low DC voltage. A buck converter typically includes a switch disposed between an input and an output of the buck converter (also referred to as a “high-side switch” in the present application), and a switch disposed between the output of the buck converter and a ground (also referred to as a “low-side switch” in the present application). The buck converter can include a control circuit to appropriately control the duty cycles of the high-side and low-side switches so as to convert a high input voltage to a low output voltage. For a buck converter to achieve a desirably high conversion ratio of input voltage to output voltage, the high-side switch needs to operate at a sufficiently low percent duty cycle. However, the duty cycle of the high-side switch is limited by its switching speed.
In a conventional buck converter, a high voltage silicon field effect transistor (FET), such as a high voltage metal oxide semiconductor FET (MOSFET), can be utilized for each of the high-side and low-side switches. However, as a result of a limitation in the switching speed of the high voltage silicon FET, it can be difficult for a conventional buck converter to achieve a conversion ratio (i.e. the ratio of input voltage to output voltage) that is much greater than approximately 10.0. As a result, two or more conventional buck converter stages can be required to convert a high DC voltage, such as approximately 310.0 volts, to a significantly lower DC voltage required to drive a particular load, thereby significantly increasing cost.